Because the canvas remained attached to the framework, retractable awnings allowed a more flexible approach to shading (shopkeepers and owners could incrementally adjust the amount of awning coverage depending upon the weather conditions).
On the other hand, Attrition wounds are caused by rubbing or friction like grinding of the teeth. 4. Abrasion occurs when one rock hit another surface. Attrition can be termed as a form of river or coastal erosion where the surface is washed away.here is also another meaning to attrition. Attrition also refers to a staff reduction in companies through usual process like resignation or retirement. Summary. 1. Abrasion is restricted to superficial destruction; attrition is not limited to such destruction. 2.
Allopatric speciation (from the ancient Greek allos, other + Greek patris, fatherland) or geographic speciation is speciation that occurs when biological populations of the same species become vicariant, or isolated from each other to an extent that prevents or interferes with genetic interchange.he extent to which a geological barrier can effectively isolate a population correlates to the mobility of the organism or its offspring. For example physical barriers such as canyons may effectively block migration and dispersal of small mammals; however, have little impact on flying birds or wind-borne seeds.